[ http://issues.apache.org/jira/browse/LUCENE-446?page=comments#action_12358936 ]
Yonik Seeley commented on LUCENE-446: ------------------------------------- This newest version simplifies a lot of cruft from the previous version. A FunctionQuery takes a ValueSource. The ValueSource produces a DocValues object for a specific IndexReader (It's like a lucene scorer). The ValueSource is also used as input to functions, which are ValueSources themselves. So, you can do things (symbolically), like int(fieldx) float(fieldx) ord(fieldx) rord(fieldx) linear(fieldx,1,2) linear(rord(fieldx),1,2,3) reciprocal(linear(fieldx,1,2),3,4,5) A useful one for boosting more recent dates might be: reciprocal(rord(mydatefield),1,1000,1000) I'm not sure if this is the final form yet... perhaps the division between ValueSource and Query could be erased such that every value source is a query already (so that you don't need to pass it to a FunctionQuery). It would also be nice to freely mix a lucene Query and a ValueSource so that you could do something like: product(luceneQuery, val(fieldx)) or even product(luceneQuery1, luceneQuery2) Of course, I haven't done the "product" function yet... right now, the normal way tocombine with other queries to influence the score is to put it in a boolean query: +other_lucene_query_clauses +function_query^.1 the score from the function query is added to the other query. > FunctionQuery - score based on field value > ------------------------------------------ > > Key: LUCENE-446 > URL: http://issues.apache.org/jira/browse/LUCENE-446 > Project: Lucene - Java > Type: New Feature > Components: Search > Versions: 1.9 > Reporter: Yonik Seeley > Attachments: function.zip > > FunctionQuery can return a score based on a field's value or on it's ordinal > value. > FunctionFactory subclasses define the details of the function. There is > currently a LinearFloatFunction (a line specified by slope and intercept). > Field values are typically obtained from FieldValueSourceFactory. > Implementations include FloatFieldSource, IntFieldSource, and OrdFieldSource. -- This message is automatically generated by JIRA. - If you think it was sent incorrectly contact one of the administrators: http://issues.apache.org/jira/secure/Administrators.jspa - For more information on JIRA, see: http://www.atlassian.com/software/jira --------------------------------------------------------------------- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
